Differential



June 22, 1926. 1,590,129

H. C. STRATFORD DIFFERENTIAL File d Dec. 24 1924 2 Sheets-Sheet 1 v INVENTOR Hugo CAMPBELL STRATFfiRD ATToRNE YS June 22 ,1926.

H. C. STRATFORD DIFFERENTIAL Filed Dec. 2 1924 2 Sheets- Sheet 2 uvvezvrog' Huqo CAMPBELL 87'RATFOR0 A 7 TORNEYS Fatented June 22, 1926.

HUGO CAMPBELL STBJATFORD, 0F VANCOUVER, BRITI$H COLUMBIA, CANADA.

DIFFERENTIAL.

Application filed'beccmber 24,192. Serial N0.'757,836.

My invention relates to improvements in differentials for use on automobiles and the like, the objects of which are to provide means whereby a positive and independei'it drive is communicated to each road wheel from the drive ring, so that in the event of traction being lostto one road wheel tl'irough mud or other slippery footing, traction may be obtained by the other. Another object is to provide means whereby the pawls effecting rotation of the shafts in one direction shall be resiliently but firmly held in place in the ratchet wheels and the corresponding pawls for etfectingyrotation in the opposite direction shall be lifted out of engagement of the ratchet wheels. A still further object is to provide the sets of pawls through which the drive is communicated 'to "theroa'd Wheels in opposite directions may engage their respective ratchet slots when the differential is at rest and alsoforproviding that no motion is lost betweenthepawls and ratchets when a change of driving direction is effected.

The invention consists of a pair-of ratchet wheels each mounted on a shaft and enclosed within a casing to which the drive ring is fittedand carrying a plurality of pawls by which a drive is established between the drive ring and the shafts, as will be moref-ully de scribed in the following specification in which Fig. 1 is a sectional view taken on the line 1-1 of Figure 2.

Fig. 2 is a sectional View taken on the line 272 of Figure 1, with the crown gear omittec.

Fig. 3 is a sectional view taken on the line 3-3 of Figure 1.

In the drawings like characters of reference indicate corresponding parts in each figure.

The numerals 1 and 2 indicate a pair of shafts in axial alignment with each other and each having a ratchet wheel 3 keyed upon its inner end, the wheels are provided with a circular boss 4 which is ournalled in the casing 6, the periphery of the ratchet wheels is provided witha plurality of transverse ratchet slots 5. i

The numeral 6 indicates casing which is formed of two annular flanges 7 having central bores 8 in which the bosses i of the ratchet wheels 3 are journalled and a plurality of inturned lugs or spacers 9 through which bolts 10 are driven to hold the casing 6 together.

The numeral 11 indicates a drive ring which is transversely slotted as at 12, the

purpose of Which will hereinafter appear.

One edge of the ring being inwardly flanged as at 13 to engage the outer face of one of the flanges 7 and the other edge being outwardly flanged as at lit to form a seating for the crown gear 15 and to receive an annular cover ring 16 by which the outer face of the other flange 7 is engaged. Carried in opposing recesses 17 on the inner faces of the flanges 7 are a plurality of pairs of pins 18 upon each of" which pairs of pawls 19 and 20 are mounted, the pawls 19 separately engaging each ratchet wheel 3 to drive it in a forward direction and the pawls .20 separately engaging each ratchet wheel to drive it in a rearward direction. The pawls are so spaced as to permit of all of them being engaged'in the slots 5, when the differential is at rest.

The pawls 19 and 20 are each provided with an upstanding lug 21 in which tapering :re-

cesses 22 are provided to form a housing for the ends of a coil spring 23 which extends between opposing pawls 19 and 20 so that each spring exerts a resilient pressure on one pawl designed to actuate in a forward direction and one to actuate in a rearward direction. The lugs 21 project into the slots 12 of the drive ring 11 so that as the crown gear 15 and the ring 11 are turned in a forward or clockwise direction, the side of each slot engages the lug 21 of all the pawls 20, raising them from contact with the ratchet wheel and simultaneously imparting a resilient pressure through the springs 23 to depress the pawls 19 into the slots 5 of the ratchet wheels 3.

Projecting from the peripheral edge of each of the annular flanges 7 are a plurality of lugs 24 somewhat less in length than the width of the slots 12 in the drive ring 11.

Due end of each of the lugs 2% comes into ment with the axis of the recess of the cor-' responding pawl, but the provision of tapering sides to such recesses prevents the overrun the crown gear the action of the casing and all the pawlswill be reversed, so as to prevent the free rotation of the ratchet wheels, thus taking up the drive in the opposite direction. i

It will thus be seen that I have invented a differential through which a positive drive is automatically transmitted to either shaft or wheel, which is capable of giving traction to the vehicle to which it is fitted.

What I claim as my invention is:

1. The combination with a pair of aligned shafts and a driving element, of a pair of ratchet wheels mounted upon the shafts, a pair of annular flanges each having peripheral projections, between which flanges pawls are carried, said pawls vbeing oppositely arranged and in pairs and having upwardly extending lugs, spring means ex tending between the lugs adapted to hold the pawls normally in engagement with the ratchet wheel, one of each pair being adapting a pair of aligned driven members,

ratchet wheels fixed to the adjoining ends of said members, a pair of spaced discs rotatable with respect to said driven members and receiving the latter therethrongh, a drive ring turnablymounted on the peripheral surfaces of said discs and provided with a series of circumferentially spaced slots, a plurality of pivot pins arranged in pairs extending between and'terminally supported by said discs, a pair of forward driving pawls pivotally supported by one pin of each pair, a pair of reverse driving pawls pivotally supported by the remaining pin of each pair, opposing lugs carried by the forward and reverse driving pawls of each pair and projecting into one of the slots of the drive ring, a coil spring confined between the lugs of each opposing pair and accessible through the slot receiving said lugs, the ratchet engaging terminal of each forward driving pawl extending toward the corresponding terminal of a reverse driving pawl and spaced from the latter terminal a distance approximating the width of the teeth of the ratchet wheels.

Dated at Vancouver, BL C. this 12th day of December, 1924.

HUGO CAMPBELL STRATFORD. 

